Clamp for dental inlay rings and the like



April 17, 1934. w. s. RICE 1,955,343

CLAMP FOR DENTAL INLAY RINGS AND THE LIKE Filed May l1, 1931 Patented Apr. 17, 1934 UNITED STATES Ars GLAll/AEJ7 FOR DENTAL INLAY RINGS AND THE LIKE Application May 11, 1931, Serial No. 536,410

1 Claim.

My invention relates to a clamp adapted for use particularly with dental inlay rings and the like.

Dental inlays and the like made of cast gold or other material are usually formed by providing a wax pattern which is attached to a sprue and after being given an initial coat of first investment material, the pattern is then immersed in a plastic investment material which is allowed to harden. The wax pattern is then melted out or dissipated leaving in the hardened investment a cavity which is then filled with molten gold or other material of which the inlay or the like is to be formed. After the inlay has cooled the investment is broken away or otherwise disposed of.

The wax pattern with the initial application of first investment is usually immersed in the investment material which forms the mold body for the inlay by applying the sprue with the wax pattern thereon to a crucible former whereupon the inlay ring is applied over the pattern and endwise against the crucible former. r1`he ring is then lled or substantially lled with the investment material for forming the main body of the mold with the wax pattern immersed therein.

In practice, it has been found that gold, for example, will shrink upon cooling and therefore, in order to allow for this shrinkage, it is customary to expand the wax pattern before the initial set of the investment material surrounding the same takes place. This is preferably accomplished by immersion of the inlay ring filled with investment material and with the wax pattern embedded therein in a body of water heated tothe desired temperature.

The principal object of my present invention is the provision of a clamp which is adapted to close the invested ring or iiask and provide a substantially water-tight seal to enable the operator to immerse the invested flask in water without leakage.

Another object of my present invention is to provide a simple and eicient clamp that may be applied to and removed from the ring or iiask with facility.

The adaptability of the clamp of my present invention for use with various types of inlay rings and further objects and advantages of my present invention will hereinafter appear.

My invention is illustrated in the accompanying drawing, in which:

Figure 1 is a perspective view of a clamp embodying my present invention, showing the Same applied to a dental inlay ring;

(Cl. 18-33l Figure 2 is a vertical section taken on the line 2 2 of Figure 3; and

Figure 3 is a fragmentary detail section taken on the line 3--3 of Figure 2 and showing the cap for the inlay ring in plan.

Referring to the drawing the particular embodiment of the invention selected for illustration comprises a unitary generally L-shaped clamp body lf). The iaw 11 is in one piece with the arm l2 of the body 10 and is disposed sub- 65 stantially normal the lower end of the arm 12. This jaw 11 is formed to constitute a support for the inlay ring 13 and Crucible former le, which is usually applied to one end of the ring 13.

The ring support comprises a at web-like base proper 15 having a thickened generally U-shaped margin 16 forming a generally U-shaped raised ridge or shoulder 17 along the sides and inner end cf the base 15. The spacing of the sides of this raised ridge or shoulder 17 is substantially equal 15 to the diameter of the base 18 of the Crucible former 14, and the spaced sides of this ridge open outwardly from the arm 12 to receive the base of the Crucible former whereas that portion of the shoulder 17 surrounding the inner end of the 80 base l5 closely follows the adjacent periphery of the base 18 to position and hold the Crucible former and thereby the adjacent end of the ring 13 in place upon the support l1.y

The CrucibleA former 14 per se forms no part of 85 my present invention. Suihce it to say that the 4former shown comprises a conical metal wall having the base 18 formed integrally therewith Vand that the apex of the conical wall has an aperture 19 for receiving and positioning the sprue 90 2O with the attached model21 substantially axially of the crucible former and with the model 21 above the apex of said former.

In the illustrated embodiment of the invention the inlay ring 13 is in the form of a plain straight 95 ring cut from brass tubing and provided internally with an annular groove 22. rlhis ring is merely illustrative and it will be understood to those skilled in the art that the clamp of my present invention is adapted for use with practically ,1.00 any type of ring or flask.

The particular details of the sprue 20 per se likewise form no part of the present invention. Suiiice it to say, therefore, that the sprue 20 coinprises a metal pin, one end of which may be f heated and pressed into the wax pattern for the purpose of attaching the pattern thereto. The particular sprue illustrated has its upper end recessed internally at 23 to form a vacuum sprue, but the details of this are immaterial here.

The movable jaw of my improved clamp is in the form of a disk 24 formed to constitute a cap for the upper end of the ring 13. The cap 24 has an integral upstanding and substantially axial stem 25, the sides of which are splayed to t between the sides of the bifurcated outer end of the relatively short arm 26 of a bell crank lever 27. The lever 27 is pivoted at 28 upon. lugs 29 formed integral with the arm 12 by means of a pin passing loosely through the lugs 29 and anchored at its opposite ends in lugs 30 formed integral with the lever 27 and embracing the lugs 29.

The stern 25 is pivotally anchored at 32 in the bifurcated outer end of the arm 26. This pivotal anchoring may be obtained by passing a screw loosely through an aperture in one side of the bifurcated arm and loosely through any selected one of the series of apertures 33 in the stem 25 and threading the opposite end of the screw into a threaded aperture in the opposite side of the bifurcated end of the arm. By providing a series or plurality of apertures 33 in the stem 25 as shown, the pivotal attachment of the cap 24 to the arm 27 may be adjusted conveniently for inlay rings of diierent lengths.

The relatively long arm 35 of the lever 27 is formed to constitute a linger piece and the upper end of the arm 12 is formed to constitute a cooperating finger piece so that by grasping these arms between the fingers and pressing the arm 35 toward the upper end of the arm l2 the lever 27 may be swung in a clockwise direction (Figure 2) about its pivot 28 for the purpose of raising the cap 24 from the ring support 11 as shown in dotted lines in Figure 2. A spring 36 coiled about the pivot pin 28 between the lugs 29 with one end 37 bearing against the lever 27 and the other end 38 bearing against the arm 12 yieldably urges the lever 27 in a counter-clockwise direction (Figure 2) and the cap 24 down upon the adjacent end of the ring 13.

The bottom surface of the cap 24 is preferably provided with a yieldable facing for engagement with the adjacent end of the ring 13. This yieldable facing is preferably in the form of an annular ring or washer 39, of rubber or other suitable yielding material, mounted in an annular groove 40 in the bottom surface of the cap 24 in position to engage the upper end of the ring 13.

Now in order to acquaint those skilled in the art with the purpose and manner of use of the clamp of my present invention I shall now describev briefly the making of a dental inlay of cast gold or other material and the utility of my present clamp therewith:

The cavity in the tooth is usually first prepared and then filled with wax which upon removal from the cavity forms the wax pattern indicated at 21 in Figure 2. This wax pattern 2l is then attached to the sprue 20 and may be given an initial coat of first investment material by painting it thereon. The sprue 20 is then inserted in the aperture 19 in the Crucible former and the ring 13 is then applied over the pattern and to the Crucible former in the manner illustrated in Figure 2 whereupon the ring is filled or substantially lled with a plastic investment matter, indicated at 41, immersing the pattern 21 therein. The invested ring with the Crucible former in place on the lower end thereof is then positioned in the clamp with the base of the former positioned and held in place upon the support 11 by the shoulder 17. By graspingthe upper end of the arm 12 and the arm 35 between the fingers and pressing the arm 35 toward the arm 12 the cap 24 is raised against the tension of the spring 36 sufficiently to clear the invested ring to permit positioning the ring in the clamp with great ease and facility. The arm 35 is then released and the spring 36 forces the cap 24 down upon the top of the ring 13 and the yielding facing 39 rmly and tightly against the upper edge of the ring.

The former 18 and cap 24 are thereby clamped firmly in place upon the opposite ends of the ring 13 providing a water-tight or substantially Watertight seal and thereby enabling the operator tov immerse the invested ring in water without leakage as for the purpose of expanding the Wax pattern as previously pointed out.

Obviously the ring 13 may be capped and clamped to the support with the device of my present invention for other purposes than that above described, and it is to be understood that my present invention is not to be limited to the specic structure shown and described but that, in fact, wide variations in the clamp may be employed within the broader aspects of my invention, as dened in the appended claim.

I claim:

In a clamp of the class described the combination of a generally L-shaped clamp body having a dental investment ring support and an arm formed in one piece therewith and extending substantially normal thereto, said arm having a nger piece at its free end, a bell crank lever pivoted to said arm and having one arm formed to constitute a finger piece for cooperation with said rst nger piece, a cap having adjustable connection with the other arm of said bell crank lever and adapted for capping a dental investment ring, and spring means coop/arable with said bell crank lever for pressing said cap toward the ring support.

WILLIAM S. RICE. 

